Centrifugal separating-machine



R. E. LA.PHAM.

CENTRIFUGAL SEPARATING MACHINE.

APPLICATION FILED JUNE 8, 1.91.6.

1,336,968. Patented Apr. 13, 1920.

R. E. LAPHAM.

CE NTRIFUGAL SEPARATING MACHINE.

APPLICATION man JUNE 8. 1916.

1,336,968. Patented Apr. 13, 1920.

4 SHEETS-SHEET 2.

[ ififi R. E LAPHAM.

CENTREFUGAL SEPARATING MACHINE. APPLICATION FILED JUNE 8. 1916.

1,336,968. Patented Apr. 13, 1920.

4./SHEETS-SHEET 3. 7

R. E. LAPHAM'.

CENTRIFUGAL SEPARATING MACHINE.

APPLICATION FILED JUNE 3. I916.

4 SHEETSSHEET 4.

awuamtoz EEZa vkwm attoum Patented Apr. 13, 1920.

2X a so J- I mm E. mum, OF SAN rmncrseo, CALIFORNIA.

CENTRIFUGAL sErAaATING-mcmnn Specification of Letters Patent.

Application filed June 8, 1916. Serial No. 102,533.

To all whom it may concern Be it known that I, RALPH E. LAPHAM, a citizen of the United States, residing at San Francisco, in the county of San F ranc1sco and State of California, have invented certain new and useful Improvements in Centrifugal Separating- Machines, of which'the following is a specification.

tion involves means and methods designed in practice for economically effecting the separation of heavier materialsor substances from lighter materials or substances, or vice versa.

" The invention comprises primarily a centrifugally operating machine adapted to be used particularly for recovering gold or platinum values from auriferous or platiniferous sand found in vast quantities on the beaches and even far inland from the sea, in certain portions of our country. It

' is well known that what is ordinarily called the black sand above referred to, contains values of precious metal ranging in value from fifty cents to eight dollars per ton, and

while I am aware that heretofore centrifugal separating means have been proposed for use in recovering such values, I know ofnone of such machines designed in accordance with certain principles of the construction of my invention as hereinafter set forth, by which the reclaiming of the values may be eflected with the degree of economy incident to the use of my invention, the latter being an essential desideratum in the art of machines and methods to which the present improvements relate' Y I do not wish, however, to be limited to the particular use of my invention as just explained since it may be employed with great effectiveness for the separation of materials of various kinds.

In the-carrying out of the present invention I contemplate the utilization in my centrifugally operating machine of a mobile separating medium in the form of a film of mercury under control, and the use of which medium has heretofore been pro posed. The moving film of mercury moves upward from the bottom of a bowl or similar receptacle in which the pulp or -materials to be'separated are placed, and through centrifugal action the pulp spreads out and I forms a continuous flowing film likewise, moving, however, over the inner face of the mobile film of mercury, speaking particu- In-its broadest phase the present invenmixing with the latter,

.ing operation and so that the a quiescent bed of the separating medium,

as will later be-described. An especially important feature of the lnvention resides in the peculiar means and method by which the film of pulp, after it has sufficiently passed over the face of the mobile separating medium is kept from and actually separated. from contact therewith, so that the pulp film may pass off from the machine as tailings. at the conclusion of the separatmercury or separating medium of heavier specific grav- 1ty may be returned to the source of supply. or to the point of its starting movement, and used over again. Eor the last mentioned purpose I utilize jets of water projected centripetally in a manner which will be fully presented hereinafter and involving the employment of peculiarly novel instrumentalities as well as a new separating process.

Still another important feature of the invention resides in the means whereby the centrifugal action of themobile separating medium is produced, and whereby the separating medium in respect to moving as well as quiescent portions thereof is controlled to avoid liability of' flouring of the same. With the further view to maintenance of the integrity of the separating medium, and since the mercur thereof is not lost orconsumed but is 'lltillzd as a receiving face or film over again, it is contemplated to prevent contamination of the separating medium by contact with sand and watercomprising different chemical elements such as oils, by the employment of special means. The latter means is preferably electrical and intended, of course, to guard the mercury against attack thereon by foreign chemical substances, whereby this separting medium is maintained with a natural tendency to coalesce at all times. An extremely effective reaction can be 'ven to the oils and like contaminating rfii emical substances by sending a current of electricity'through the mercury film and water,

varying it to increase the coalescence of the Patented Apr. 13, 1920. p

the pulp, such ing drawings,

visions for this purpose forming an essential feature of this invention.

Among other objects of the invention are the provision of a machine of the type set forth having the advantage of portability and one in which the operating members do not have to be maintained exactly level under operating conditions whereby the machine may be moved from place to place to facilitate the supplying of the pulp or values containing materials thereto and not require nicety of adjustment when positioned for use; the provision for replenishment automatically of the supply of mercury which under operating conditions is caused to pass through the machine as the mobile separating medium, and for utilizing an auxiliary reservoir for the mercury provided for replenishment purposes, which reservoir is so connected with the main mercury reservoir from which the mobile film issues as to maintain a continuous supply of this mercury therein, as will be made more fully apparent hereinafter.

The invention involves "other and various detail features of construction of the machine hereinbefore referred to, all of which will be set forth fully in the following description and understood upon reference I thereto in connection with the accompanyin which- Figure 1 is a view partly in elevation and partly in section showing a centrifugal separating machine embodying the invention.

Fig. 2 is a vertical sectional view of the machine with certain parts shown in elevation and the main shaft broken away at the point where the driving pulley is supplied.

Fig. 3 is a horizontal sectional view taken about on the line 3--3 of Fig. 2.

Figs. 4 and 5 are fragmentary sectional views taken about on the lines 4-4 and 5-5, respectively, of Fig. 2.

Fig. 6 is an enlarged fragmentary section of the upper portion of the bowl showing clearly the mercury outlet and water inflowchamber and adjacent connections.

General construction of machine.

Describing the invention in detail, in the drawings (see Fig. 2 especially) A denotes the main bowl or receptacle for receiving the pulp or values containing materials, the same being mounted for rotation with the shaft 1 and having the false bottom 2 slightly spaced from the bottom A. The bottom 2 is held in place by means of a thread by which it screws on a central boss of the bottom A and also held by the set screw 3. The screw connection between the parts A and 2, shown at 2", affords a means for adjusting these parts relatively to control the size of the port 4 through which the mobile separating medium or bottom 2 has a long sweeplng curvature so that its upper surface affords an easy flow forthe pulp fed into the bowl A through the hopper 6, and the said bottom 2 likewise serves as a spreader for the pulp. The pulp is fed from the hopper 6 to the bowl y cal inclosing wall 8 and secured to the shaft 1 to rotate therewith. The screw 7 compels even feeding of the pulp, ordinarily sand and water containing the values, to the bowl A.

Above the hopper 6 is provided a suitable bearing 9 for the shaft 1 and a similar bearing 10 surrounded by an oil cup 11 is provided at the lower end of the shaft. At its upper end the shaft 1 carries for rotation therewith the auxiliary mercury reservoir 12 preferably made of glass and connected with the main reservoir 5 at the bottom of the bowl A, by means of a pipe the feed screw 7 having the cylindri-.

or conduit 13 extending quite a distance I through a hollow portion of the shaft 1 and thence extending radially from the shaft to a point of connection with the bowl A at the reservoir 5, at which the conduit is formed with a funnel-shaped mouth 13'.

The mercury which forms the mobile separating medium is caused by centrifugal action to pass from the reservoir 5 upward through the port 4 or space between an internal flange a on the bowl A, and the outer periphery of the bottom 2, when it takes the form of a thin film passing upward along the annular inner wall of the bowl. When the mercury in the main reservoir 5 becomes 1 so low, or approaches the danger point at which there would be no flow of said mercury through the film port 4, the gravitative and centrifugal force of-the mercury in the conduit 13 overcomes the centrifugal force at the mouth 13, whereupon the mercury flows from the reservoir 12 into the main reservoir 5 and replenishes the supply in the latter.

Beneath the bowl A is located the water reservoir 14 surrounding and fixed to the shaft 1, water being supplied to said reservoir from a supply pipe 15 connected with the lower hollow end portion of the shaft 1, which latter forms a conduit to conduct the water from the pipe 15 to the reservoir 14. Radial openings 16 in the shaft establish communication between the reservoir 14 and the hollow portion of the shaft, and a web or plug 17 separates the water supply conduit portion of the shaft 1 from the upper'hollow portion in which the conduit or pipe 13 is disposed. The reservoir 14 being rotative with the shaft 1 produces pressure incident to the centrifugal forceof the water received in said reservoir.

The bowl A is so formed t portion as to provide achamber B of peculiarl .B is constituted by a flanged annulus 18 having threaded connection with the upper, most extremity of the upper end of the outer wall of said chamberas shown at 19. Thelower end of the annulus 18 is beveled, or so formed and spaced from a flange 20 at the upper end of the bowl as to form an annular passage between the two, establishing communication between the interior of the bowl A and the chamber B. This passage may be adjusted to increase or decrease its-operative area by means of the connection 19. The upper portion of the chamber B is separated from its lower portion by-a horizontal partition 21 projecting toward forming in connection the annulus 18 and with an adjustable ring 22 screwed on the latter a passage b leading from the lower portion of the chamber B to said-upper portion. The size of the passage 6 is regulable by adjustment of the ring 22 upwardly or downwardly and thereby varying its proximity in relation to the partition 21.

The water reservoir let is connected with the chamber B by means of a plurality of conduits 23 leading upward from the 'pe-. riphery of the reservoir and of somewhat spiral formation, to the extent that the said conduits wind around the bowl A approximately a fourth or greater portion of the circumference. of said bowl,-and in a direction opposite to that in which the water flows therethrough. The purpose of the spiral formation of the conduits 23 is to render the centrifugal flow of water therethrough from the reservoir 14, more rapid and effective than would be the case-otherwise. At its upper end each conduit 23 leads intoth'e upper portion of the chamber B, as seen at 23 in Fig. 6. There is pro-- videda plurality of return conduits or pipes 24 connected with traps 25 in communication with the conduits 24 at the upper ends of the latter,the traps 25 being directly connected with the chamberBat its lower portion, or that portion beneath the partition 21. The conduits or pipes 24 furthermore startingat their upperends are curved or formed spirally imsuch a manner as to wind around and downwardly in respect to the bowl A in a direction opposite that in which said bowl revolves and in a manner similar to the formation of the conduits or pipes 23 which conduct the water from the reservoir .14 .to the chamber B, with respect to the flow therethrough. Any suitable number of the conduits 23 and 24-may be utilized.

Reverting to the main mercury reservoir 5, it should be noted that at the base of saidreservoir is provided a removable screw or plug 26, see Fig. 2, which when removed affords an opening through which the mercury and values of precious metalmay be ment of the rapidly seen at 3 at the inner side of washed out of the bowl A. In the mercury chamber 5 is disposed a casting formed so as to provide a cover 27 for the mercury reservoir, from which cover depend the vertical integral partitions 28, the parts 27 and 28 being of annular form. The partitions 28 divide the reservoir 5 into three separate compartments which are connected together by small passages provided by recesses 28' in the lower edges of said partitions and therefore the mercury is permitted to pass to the outermost portion of the mercury res-' ervoir-o as an incident to the centrifugal operation of the machine. From the outermost compartment of the reservoir 5 the mercury with its centrifugal force reduced owing to the provision of the partitions 28, is free to pass from the reservoir 5 through the port or space 4 into the body of the bowl A with just sufficient force to insurev an even feed of the separating medium to the surface of the inner wall of the bowl at which surface the medium takes the form of an annular film such as previously generally referred to. Owing to the provision of the parts 27 and 28 it becomes immaterial whether the reservoir 5 is entirely full or nearly down to the danger zone, the latter being adjacent to the funnel-shaped mouth 13 of the conduit 13.

General operation.

with are driven at the proper speed through a driving connection between a pulley 29 and any suitable source of power, such as an ordinary motor. During the rotation of the shaft 1 the mercury passes from-the reser-- voir 5 through the port 4 and spreads into the form of a mobile film operating upward along the inner surface of the bowl A, which inner surface is formed with somewhat V- shaped grooves A". Owing to the moverotating bowl A the centrifugal force of the mercury film designated w in Fig. 6 is so great that said film is pressed againstthe wall of the bowl A so densely that upward movement is compelled by the feeding of the fresh supply Q of mercury through the port 4;. The grooves A" become filled with mercury at the beginning of the movement of the mobile film and the mercury in said grooves constitutes quiescent bodies of this substance protected peculiarly but adequately by the moving film, against the sand ing upward as a film likewise, and in contact with the exposed face of the separating medium film. Obviously, values such as gold, platinum, etc. contained in the pulp moving upward in film and like form, as i the film ac, as seen in Fig. 6, being of greaterspecific gravity than the mercury at an pass through said mercury and lodge in the uppermost I or pulp passangles of the grooves A". These valuesare d signated 2 in Fig. 6. The values deposited in the quiescent bodies of mercury in the grooves A", checked in their speed of separation from the pulp, by the moving mer- :ury film, remain in the groove A until centrifugal action of the bowl A ceases.

An important phase of-the operation of the machine as before premised resides in the method of separating and passing ofi the pulp as tailings, after the values have been removed therefrom, as the pulp film and the mercury ,film reach the upper end of the bowl A, or in reality reach the chamber B. In accomplishing the above the film of pulp is caused to pass the mercury outlet passage 0 of Fig. 6 without entering said passage owing to the centripetal force of water supplied to said passage from the various conduits 23 connected with the upper portion of the chamber B. This force of the water received by the chamber B and passing therefrom through the passage 6 and the passage 0, is suflicient to keep the pulp y, see Fig. 6, from entering the passage 0, but not suflicient to prevent the mercury from flowing out of the bowl A through said passage into the portion of the chamber B beneath the partition 21. From the lower portion of the chamber B said mercury previously constituting the mobile film passes through the traps 25 and conduits 24 back to the main reservoir 5. The two films w and 3 see Fig. 6, are prevented from mixing at the upper end of the bowl A in the above manner, namely by flow of water through the passage 6 which flow must essentially be with sufiicient force to prevent the film 3 from entering the chamber B but of insuflicient force to prevent the mercury from passing into said chamber B.

Since the specific gravity of the mercury is from three to five times greater than that of the pulp, a rather wide range of pressure force of the water entering the bowl A through the passage 0 is afforded. Furthermore, it is notable that-the mercury film m is substantially five times as dense as the pulp film and the water flowing out through the passage 0 has'a tendency to wash the dense mercury film clean of sand and 'substances of comparatively light specific gravity, somewhat as though the film bending out into the chamber B as it does, werea piece of thin metal. Furthermore, it is evident that the fiow of water from the chamber B through the passage 0 performs still another function in that it tends to check or retard, but not stop, the passing outward for return to the mercury reservoir, of the film w. On this account the mercury as it flows over the flange 20 at the passage 0 is prevented from falling to pieces or scattering, with resultant "advantages of importance.

A little lime water or acid may be introduced into the machine occasionally to counteract any contaminating effect that oils or similar foreign substances in the pulp may have upon the mercury, but other means for this purpose designed especially to safeguard against the contamination of the mercury will be very shortly described. v

' As the pulp passes from the 'bowl after the separating operation is completed it overflows as tailings the rim of the bowl into a chamber D of annular form, which latter surrounds the upper portion of the bowl and is of course stationary. The tailings may pass from the chamber D through any suitable outlet, the bottom of said chamber being inclined as seen best in Fig. 2. If desired the chamber D may form a part of the casin E of the machine, which casing 7 centrifugally operating bowl having perpendicular walls, the rate at which the material moves upward depends primarily upon the inclination of the mercury wall and not wholly upon the speed of the bowl. In fact, the flow of the material upward does not increase in the same proportion as does the centrifugal force for the s eed of the bowl governs the inclination of t e mercury wall in such a manner that at a slow speed the surface of the mercury over which the pulp passes is less steep and the pulp passes out at say two feet per second. Doubling the speed of rotation of the bowl, for example, the wall of the mercury becomes steeper in gal force exerted u on it. The pulp will not movetwice as ast as before, however, since the surface of the mercury film over which it travels is more steep, or more nearly approaches the per endicular. Thus it is that the centrifuga force increasesv greater in proportion than does-the movement of the pulp, and it will therefore be seen that the separation. will be extremely effective at high speeds. Now the water pressure in my machine obviously depends upon the centrifugal force and the speed of rotation of the bowl and the pressure corresponds under these conditions to the centrifugal force exerted u on the material-in the bowl. So it is that i the ports are regulated to give a certain ressure at a predetermined speed of rotatlon of the bowl they are automatically regulated for all speeds since the pressure of the water in the chamber B rises and falls in the" same proportion as the pressure of sand and water passing over the passage 0, and said water presdirect proportion to the centrifu sure at said passage is always ample to exclude the sand from entering the chamber B, while the mercury is permitted to pass into said chamber retarded or checked in the manner previously set forth.

In view of the foregoing phase of operation of my machine it does not become necessary to provide means for adjusting any of the ports or passages, various of which have been mentioned by me, during the rotation of the bowl, something for which provision has had to be made in certain machines of "the type of the present invention. It is for bottom of the bowl, instead of projecting radially toward the axis; in other words said conduit portions are 'in a plane tangential to the inner wall of the mercury reservoir 5, see'Fig. 3

Mercury contmnination preventive means.

Reference has previously been made to the difficulties incident to the contamination of the mercury forming the mobile separating film employed in my machine and caused by different chemical ingredients of the pulp or sand and water which pass over the surface of the mercury film in the use of the latter 'over and over again. As stated before, I provide electrical means whereby to give an effective reaction to the contaminating oils and other similar ingredients in the pulp, it being true that when the electric current is caused to pass through a body of mercury, or even through a body of water overlying a body of mercury, the power of the mercury to coalesce is materially increased. Oils being very much lighter in weight than mercury, they do not come into very close contact with the mobile film of my centrifugal machine but in the long run they have a deleterious effect upon the mercury, as previously suggested, and I have also taken in consideration in providing against such effect, the power of dissolving other metals and thus becoming impure or sick. In my machine, owing to the fact that it has to hold the gold and platinum values recovered regardless of the condition of these metals in respect to carrying substances allied with respect to mercury, I refer in this connection to the fact that the gold values may be rusty or coated with oxids or other impurities which the mercury cannot throw ofl without outside aid. The use of an electriccurrent accomplishes the above result most effectively, the current being of an intensity to prevent electro-deposition, and the provision I have made for the use of the current is seen on reference to Figs. 1 and 2 of the drawings, in which 30 and 31 are collecting rings with which wires 32 leading to any source of supply of electric current are connected. The electrode 33 in the auxiliary mercury reservoir 12 is connected with the ring 30.- The ring 31 is connected by a wire 34 with an electrode 35 located in the chamber B. Insulation is provided between the rings 30 and 31 and the connections leading to the electrodes 33 and 35 so that the electric current passes through the mercury in the conduit 13 to the mercury in the reservoir 5 and thence up the wall of the bowl A to the chamber B where it passes through the electrode 35, completing the circuit.

The electrode 35 extends into the bank of mercury which forms in the chamber B and makes connection also with the mercury on the wall of the bowl A by means of the mercury which passes through the passage C, and also by means of the water in the chamber B when the mercury does not form the connection. The electric current will, of course, also pass through the conduits 24 when the latter become full of mercury.-

An important phase of the operation of this invention is involved in the peculiar action of the mercury separating medium in association with the bowl A. As previously suggested, the bowl A is made primarily of copper and on this account it will be evident that the mercury has a tendency to readily amalgamate with the bowl, so to speak. Said amalgamation is not designed for purposes of extraction of the gold, the grooves on the inner surface of the latter being intended to retain the values. However, the composition of the bowl is such that the amalgamation specified tends to hold the mercury in a solid mass over the entire inner surface of the bowl and especially on the bottom of the hydraulic chamber B. The amalgamating action of the mercury with respect to the bowl is designedly more than the mere silvering action of a plate or surface owing to the fact that the mercury moves in a film of sufficient depth or thickness to be called liquid mercury. lVhen the separating film operating in a bowl A reaches the chamber B, owing to the affinity of the mercury with respect to the substance from which the bowl is made the film will adhere closely with a coalescing action to the lower horizontal portion or bottom of the chamber B having an amalgamating contact, so to speak, with said portion of the chamber. This action of the mercury is furthermore facilitated by reason of gravity and the pressure of the water entering the chamber B from the conduits 23. Practically speaking, therefore, the mercury film passing off through the chamber B resembles somewhat a thin sheet of solid metal. A bank of mercury of considerable depth is maintained at the outer lower corner of the chamber B so that should any sand find its way into the chamber it cannot come into contact with and thereby possibly clog the openings leading to the trap 25. In this way these openings are kept free at all times. Were it not for the amalgamating action of the mercu in respect to the inner wall of the bowl and the base of the chamber B, if a globule or globules of mercury of small size should b'reak loose from the film the same might occasionally' be forced out and lost with the tailings.

. Detail features.

Referring especially to Fig. 6, it may be noted that the trap of each mercury conduit 24 is provided not only to connect the conduit with the chamber B because said trap will become filled and remain full of mercury owing to the centrifugal action of the machine, mercury through it and through the conduit 24 with which it isassooiated. Owing to the provision of the trap '25 thewater entering the chamber B from the conduits 23 is compelled to pass out through the passage eand prevented from passing out through the traps 25.

There is provided at the lowermost portion of the false bottom 2 a plurality of openings 2' that allow the mercury falling upon the bottom 2 to reach the reservoir 5 when the machine is stopped for the cleanup. When it is desired to remove the values and mercury from the machine the latter is stopped and then rotated slowly, whereupon the mercury immediately finds its way intov the reservoir 5 to be drawn oif at the opening for the plug 26.

The bowl A is preferably made of a casting composed of 90 per cent. copper and 10 per cent. aluminum. The copper composition is employed in order to produce the surface best suited for the flow of the mercury, and not intended to be used as a silvered surface for purposes of amalgamation, except for the mercury.

The reservoir 14 is formed with a plurality of concavities at the outermost portions of which are provided the connections with the conduits 23, said concavities being formed so as to be conducive to the generating action. of a maximum centrifugal force of the water ,in the reservoir 14 incident to the rotation of the latter.

As seen best in Fig. 3 the cover 27 of the main mercury reservoir 5 is formed with re- .but allows for the flow of the ing cesses at its inner andouter edges designated at 27 and 27 Themercury leaves the reservoir 5 by way of the openings established by the recesses 27 Any water accumulating in the reservoir 5 is permitted to find its way out through'the openings established by the recesses 27 T and the openings 2 as seen best in Figs. 2 and 3.

The pressure .of the water passing through the passage 0 is regulated by adjustment of the annulus 18 by means of the threads 19.

The term pulp as used herein is intended to cover broadly any mixed materials the separation of which in one way or another is intended to be compelled by the use of the present machine. Ordinarily this pulp' would be combined sand and mintaining. a separating medium, means for supplying pulp to the bowl for separation, means for rotating the bowl whereby to cause the separating medium to traverse the inner wall of the bowl, and to cause movement of the pulp over and through the separating" medium according to the specific gravities of -its constituents, and means opposing the outflow of the separatmedium adapted to act positively on the separating medium and the pulp at a predetermined point in their movement whereby to permit movement of the former in one direction and cause movement of the latter in another direction.

2. In a centrifugalw-separator, the com-- bination of abowl having a reservoir conmeans for rotating the bowl whereby to cause the separating medium to traverse the inner wall of the bowl, and to cause movement of the pulp over and through the separating medium according to the specific gravities of its constituents, the bowl, having separate outflow passages for the pulp tailings and for the separating medium, and means to produce a positive force in opposition to the outflow of the separating medium for acting on the tailings and separating medium to direct the same to their respective outflow passages at the conclusion of the separating operation.

3. In a centrifugal separator, the combination of a bowl having a reservoir contaming a separating medium, means for supplying pulp to the bowl for separation, means for rotating thebowl whereby to Cause the separating edium to traverse thev 105 taining a separating medium, means forsupplying pulp to the bowl for separation,

cific gravities of its constituents, the bowl having separate outflow passages for the pulp tailings and for the separating medium, and means for introducing water under pressure into the bowl in opposition to the outflow of said medium to act on the.

tailings and separating medium and thereby separate the same so that they may pass to their respective outflow passages.

4. In a centrifugal separator, the combination of a bowl having a reservoir containing a separating medium, means for supplying pulp to the bowl for separation, means for rotating the bowl whereby to cause the separating medium to traverse the inner wall of the bowl, and to cause movement of the pulp over and through the separating medium according to the specific gravities of its constituents, the bowl having separate outflow passages'for the pulp tailings and for the separating mev dium, means for introducing water under pressure into the bowl to act on the tailings and separating medium and thereby separate the same so that they may pass to their respective outflow passages, and a reservoir for supplying the water introduced into the bowl and rotative for causing centrifugal movement of the water.

5.. In a centrifugal separator, the combination ofa bowl having a reservoir containing a separating medium, means for supplying pulp to the bowl for separation, means for rotating the bowl whereby to cause the separating medium to traverse the inner wall of the bowl, and to cause movement of the pulp overand through the separating medium according to the specific gravities of its constituents, the bowl having separate outflow passages for the pulp tailings and for the separating medium, means for introducing water under pressure into the bowl to act on the tailings and separating medium and thereby separate the same so that they may pass to their respective outflow passages, and a reservoir coaxial with the bowl for supplying the water introduced into-the bowl and rotative therewith for causing centrifugal movement of the water.

6. In a centrifugal separator, the combination of a bowl having a reservoir containing a separating medium, means for supplying pulp to the bowl for separation, means for rotating the bowl whereby to cause the separating medium to' traverse the inner wall of the bowl, and to cause movement of the pulp over and through the separating medium according to the specific gravities of its constituents, the bowl having separate outflow passages for the pulp tailings and for the separating medium; means for introsages, a reservoir for supplying the water introduced into the bowl and rotative for causing centrifugal movement of the water, and conduits connecting the water reservoir with the outflow passage for said separating medium and inclined in a direction opposite the direction of rotation of the bowl.

7. In a centrifugal separator, the combination of a rotative bowl to receive pulp to be separated, means for supplying a nonaqueous mobile separating medium to said bowl, an outflow chamber communicating with the bowl and through which the mobile separating medium may pass, a water reservoir, and conduits connecting the reservoir with said outflow chamber to conduct water to and through said chamber into the bowl under pressure insuflicient to prevent the separating medium from entering and passing off through the chamber but suflicient to prevent the tailings, from doing likewise ivhereby the latter pass on to a separate outet.

8. In a centrifugal separator, the combination of a rotative bowl to receive pulp to be separated, means for supplying a nonaqueous mobile separating medium to said bowl, an outflow chamber communicating with the bowl and through which the mobile separating medium may pass, a water reservoir, conduits connecting the reservoir with said outflow chamber to conduct water to and through said chamber into the bowl under pressure insuflicient to prevent the separating medium from entering and passing off through the chamber but suflicient to prevent the tailings from doing likewise whereby the latter pass on to a separate outlet, and means to rotate said reservoir to create by centrifugal action the desired pressure of the water in said conduits.

9. In. a centrifugal separator, the combination of a rotative bowl to receive pulp to be separated, means for supplying a nonaqueous mobile separating medium to said bowl, an outflow chamber communicating with the bowl and through which the mobile separating medium may pass, a water reservoir coaxial with the bowl and rotative therewith, conduits connecting the reservoir with said outflow chamber to conduct water to and through said chamber into the bowl under pressure insufficient to prevent the separating medium from entering and passing off through the chamber but sufficient to prevent the tailings from doing likewise whereby the latter pass on to a separate outlet, and means to rotate said reservoir to create by centrifugal action the desired pressure of the water in said conduits.

10. In a centrifugal separator, the combination of a bowl having a reservoir containing a separating medium, means for supplying pulp to the bowl for separation, means for rotating the bowl whereby to cause the separating medium to traverse the inner wall of the bowl, and to cause movement of the pulp over and.through the separating medium according to the sepecific gravities of its constituents, the bowl having separate outflow passages for the pulp tailings and for the separating'medium, means to produce a positive force acting on the tailings and separating medium in opposition tp the centrifugal force generated by rotation of the bowl, whereby to separate the tailings andseparating medium and facilitate their movements to their respective outflow pasconduct the separating medium to the latter to be used over again, and means for washing the separating medium clear of foreign matter before it enters said conduits. 12. In a centrifugal separator, the combination of a rotative bowl to receive pulp to be separated, an outflow chamber communicating with the bowl and through which a mobile separating medium may pass, the bowl having a reservoir from which the separating medium issues by centrifugal movement, and conduits stationary upon the bowl and'leading from the outflow chamber back to the reservoir to conduct the separating medium to the latter to be used over again, and arranged in the same general direction as the axis of the bowl but curving in a direction opposite the direction of rotation of the latter.

13. In a centrifugal separator, the combinationof a rotative bowl to receive pulp to I be separated, an outflow chamber communieating with the bowl and through which a mobile'separating medium may pass, a water reservoir,and conduits connecting the reservoir with said outflow chamber to conduct water to and through said chamber into the bowl under pressure insuflicientto prevent the separating medium fromentering and passing ofi through the chamber but sufficient to prevent the tailings from doing likewise whereby the latter pass on to a separate outlet, a reservoir on the bowl to hold and supplythe separating medium, and

conduits to conduct the separating medium from said outflow passage to said reservoir.

14. In a centrifugal separator, the combination of a rotative bowl to receive pulp to be separated, an outflow chamber communieating withthe bowl-at the upper peripheral portion of the latter and through which a mobile separating medium maypass, a water reservoir, conduits connecting the reservoir with. said outflow chamber to conduct water to and through said chamber into the bowl under pressure insufficient to prevent the separating medium from entering and passing off through the chamber but suflicient to prevent the tailings from doing likewise whereby'the latter pass on to a separate outlet, a reservoir on the'base of the bowl to" hold and supply the separating medium, and conduits to conduct the separating medium from said outflow passage to said reservoir, all of said conduits being curved spirally about the bowl and in a direction opposite and through said chamber into the bowl" under pressure insuflicientto prevent the separating medium from entering and passing off through the chamber but sufficient to prevent the tailings from doing likewise whereby the latter pass on to a separate outlet, and means whereby to vary the operative area of the portion of the outflow chamber communicating with the bowl.

16. In a centrifugal separator, thecombination of a rotative bowl to receive pulp to be separated, an outflow chamber communicating with the bowl and through which a mobile separating medium may pass, a water reservoir, conduits connecting the reservoir with said outflow chamber to conduct water to and through said chamber into the bowl under pressure insuflicient to prevent the separating medium from entering and passing off through the'chamber but sufficient to prevent the tailings from doing likewise whereby the latter pass on to a separate outlet, conduits for conducting the separating medium from the outflow chamber, and

' means to prevent the water introduced into the outflow chamber from passing off through the conduits for the separating medium. a

17. In a centrifugal separator, the combi nation of a rotativebowl to receive pulp to be separated, an outflow chamber commumeating with the'bowl and through which a mobile separating medium may pass, a water reservoir, conduits'connecting the reservoir with said outflow chamber to conduct water:

under. pressure insuflicient to prevent the separating medium from entering and passing ofl through the chamber but suflicient to prevent the tailings from doing likewise whereby the latter pass on to a separate outlet, conduits for conducting the separating medium from the outflow chamber, and means to retard the flow of the separating medium through the last named conduits to prevent the water from entering said conduits.

18. In a centrifugal separator, the combination of a rotative bowl to receive pulp to be separated, an outflow chamber communieating with the bowl and through which amobile separating medium may pass, a water reservoir, conduits connecting the reservolr with said outflow chamber to conduct water to and through said chamber into the bowl under pressure insufficient to prevent the separating medium from entering and passing off through the chamber but sufiicient to prevent the tailings from doing likewise whereby the latter pass on to a separate outlet, conduits for conducting the separating medium from the outflow chamber, and

' means to retard the flow of the separating medium through the last named conduits including traps in the length of the latter to prevent the water from entering said conduits.

19. In a centrifugal separator, the combination of a rotative bowl adapted to receive the material to be .separated, a reservoir carried by said bowl for a separating medium, a false bottom for said bowl so arranged therein as to provide a passage throu h which the separating medium may pass rom the reservoir in performing its separating function, means for rotating the bowl to causecentrifugal movement of the separating medium through said passage, means to adjust the bowl and false bottom relatively whereby to vary the operative area of said passage, a cover for said reservoir, and partitions carried by said cover and-dividing the reservoir into a plurality of compartments, said cover and partitions having passages to permit the separating medium to pass into the bowl through the first named passage.

20. In a centrifugal separator, the combination of a rotative bowladapted to receive the material to be separated, a reservoir carried by said bowl for a separating medium, a false bottom for said bowl so arranged therein as to provide a passage through which the'separating mediummay pass from the reservoir in performing its separating function, means for rotating the bowl to cause centrifugal movement of the separating medium through said passage, a cover for the said reservoir, partitions carried by remote from the first named passages.

21. In a centrifugal separator, the combination of a rotative bowl adapted to receive the material to be separated, a reservoir carried by said bowl for a separating medium, a false bottom for said bowl so arranged therein as to provide a passage through which the separating medium may pass from the reservoir in performing its separating function, means for rotating the bowl to cause centrifugal movement of the separating medium through said passage, a cover for the said reservoir, partitions carried by said cover and dividing the reservoir into a plurality of compartments, said cover and partitions having passages to permit the separating medium to pass into the bowl through the first named passage, the said reservoir being located at the base of the bowl, an outflow chamber located at the upper peripheral portion of the bowl and of greater diameter than the latter, and return conduits leading from said outflow chamber to the compartment of the reservoir more remote from the first named passage.

22. In a centrifugal separator, the combination of a shaft, a. bowl fixed thereon for rotation therewith, a water reservoir fixed to the shaft for rotation therewith, means for supplying pulp to the bowl, and for separating said pulp while operated on within the bowl, including a mobile separating medium, an outflow chamber for said separating medium carried by the bowl, and water conduits leading from the water reservoir to said outflow chamber and adapted to act upon constituents of the pulp separated in the bowl whereby to facilitate the passage of the separating medium and separated materials of equal or greater specific gravities through and from said outflow chamber.

23. In a centrifugal separator, the combination of a shaft. a bowl fixed to said shaft for rotation therewith, a reservoir on said bowl adapted to contain a separating medium, a water reservoir fixed to said shaft, an outflow chamber on the bowl through which the separating medium is adapted to pass off, conduits connecting the water reservoir with the outflow chamber aforesaid to direct waterunder pressure against the separating medium as it passes to the outflow chamber, a supply conduit-for the separating medium leading through the shaft and connected with the reservoir for said medium, and a supply conduit leading through the shaft and in communication with the water reservoir for supplying water to the latter.

24. In a centrifugal separator, the combination of a bowl, a main mercury reservoir on said bowl adapted to supply mercury in the form of a mobile separating film operating centrifugally along the wall of the bowl, an outflow chamber from the merand the associated conduits, whereby the' relative movement and pressures of the mercury and water remain the same through automatic centrifugal action of the various parts referred to.

25. In a centrifugal separator, the combination ofa bowl, a main mercury reservoir on-said bowl adapted to supply mer- :ury in the form of a mobile separating film operating centrifugally along the wall of the bowl, an outflow chamber from the mercury reservoir located at the peripheral portion of the bowl, a water reservoir rotative with the bowl, conduits connecting said water reservoir with the outflow chamber to act on the mercury as the latter enters the outflow chamber whereby to separate the tailings from the mercury at such time, a return conduit leading from the outflow chamber for conducting the mercury back to the mercury reservoir, an auxiliary mercury reservoir mounted on the shaft, a conduit connecting said reservoir with the main mercury reservoir and extending radially from the shaft to its point of connection with the main mercury reservoir, and means for rotating the bowl,-water and mercury reservoirs, and the associated conduits, whereby the relative movement and pressures of the mercury and water remain the same through automatic centrifugal action of the various parts referred to.

26. The method of separating material comprising constituents of different specific gravities which consists in producing a. flow of separating medium of relatively great specific gravity, causing the material to be separated to pass over said separating mediumin contact therewith so that the constituents of said material of greater specific gravities than the separating medium may stituents of lighter specific gravities will be detained from passing into or through the separating medium, and then directing water against the separating medium with force insufficient to prevent movement of the latter in the direction of the force exerted by said water but sufficient to prevent similar movement of those constituents of the material being separated which are of less specific gravities than that of the separating medium.

27. In a centrifugal separator, the combination of a bowl having an inner wall composedof copper, means for supplying mercury to'the bowl in -the form of a mobile separating film operating by centrifugal action along said wall in such a manner as to have a tendency to amalgamate with the wall, means for supplying pulp to the bowl to be operated on by the mercury for separation of constituents of said pulp, and means cooperatin with the bowl and separating film for e ecting separating action including a hydraulic chamber provided on the bowl and adapted to receive the mercury after it has traversed the wall of the bowl, and means for introducing a liquid under pressure into said hydraulic chamber for preventing tailings from flowing off with the mercurial film. I

28. In a centrifugal separator, the combination of a bowl having an inner wall composed of copper, means for supplying mercuryto the bowl in the form of a mobile separating film operating by centrifugal action along said wall in such a manner as to have a tendency to amalgamate with the wall, means for supplying pulp to the bowl to be operated on by the mercury for separation of constituents of said pulp, means cooperating with the bowl and separating film for effecting separating action includsaid bowl, means for supplying mercury to the bowl in the form of a mobile separating film traversing the inner wall of the bowl, a hydraulic chamber carried by the bowl, and means for introducing a liquid into the hydraulic chamber under pressure so as to cause the mercury entering the chamber to move in close contact with the bottom of the chamber.

30. In a centrifugal separator, the com,-

bination of a bowl, means for bowl, means for operating said supplying mercury to the bowl in the. form of a 'mob' 1le separating film traversing the inner wall of the bowl,

5 a hydraulic chamber carried and means for, introducing a by the bowl,

liquid into the hydraulic chamber under pressure soas to cause the mercury entering t he chamber to with the bottom of the chamber, the portions of the chamber and 10 the bowl in contact with which the mercurial separating film operates being com posed largely of copper.

move in closecontact Intestimony whereof I affix my signature. I V

RALPH E. LAPHAM. 

